Manual WSAT program (2010.01).


This is the manual of wsat, the program to receive high resolution weather satellite pictures of NOAA and Meteosat. Currently only the so-called "Rob Alblas decoder" is supported.
The HTML-version of this manual is interactive: click on a menu item to jump to the description of that item.

Starting the program.

wsat may be started by clicking an icon, by means of a command shell or by means of a script (e.g. autoexec.bat). In the last case automatic recording is possible.


  wsat {options} [file]

         -i <file>            read <file>
         -sn                  south-north (flip hor and ver)
         -w <width>           Window width (default: 400)
         -h <height>          Window height (default: 300)
         -record <sat:chan>   Auto-record; exit program if done
           <sat:chan>         specify satellite and channels
           <sat>              hrpt | chrpt | hri
           <chan>             1-5, a, g (hrpt)
                              1-0, a, g (chrpt) (0=channel 10)
                              g (hri)
                              a=all channels
                              g=generator mode (only usefull for test)
          -crecord <sat:chan> Same as -record, but record 'forever'
          -batch <sat:chan>   Batch-record; exit program if done.
                              Same as -record, except no graphical mode.

          -cbatch <sat:chan>  Same as -batch, but record 'forever'

          -log                batch messages in wsat.log in 
                              home dir. instead of in shell
         wsat                     start wsat
         wsat ned.gif             start and read in file 'ned.gif'
         wsat -record hrpt:124    record HRPT channels 1/2/4
         wsat -record chrpt:1290  record CHRPT channels 1/2/9/10
         wsat -record hrpt:a      record HRPT, all channels
         wsat -record hri         record HRI
         wsat -record hrpt:ag     record HRPT generator mode
Note: See Interface preferences: Select hardware for automatic switching of the decoder to the right type.

More about commandline options.

Overview program; main menu.

Menu: File.


Open an existing picture file:

Delete a file: Select a file, then press 'Delete file'.


Close current file. Normally 'wsat' only closes a file if a new file is selected for viewing. If a file is first viewed and then has to be renamed or deleted outside 'wsat' (e.g. with a file manager) the file has first to be closed.

Save as.

Save current picture.

File types supported:

Note that for translating HRPT into another format (GIF, PGM, PPM) information is lost (10 bits --> 8 bits per pixel).
luminance settings are used to determine which bits are selected:
Lmaxbits saved
> 5119 ... 2
<= 511 and > 2568 ... 1
< 2567 ... 0

If filetype PPM is choosen and, at the same time, the View->Channel_map is active a color picture will be saved, as specified in the View->Channel_map window. Also, alignment is done, if desired.
To save a CHRPT picture in color:

Note: Don't exit the View->Channel_map window before saving the picture. (Iconizing is, however, no problem.)

Sat info.

Information about the current file s shown. For HRPT and HRI files the frame header info is also shown; by clicking on 'Prev' or 'Next' info in a header of a certain frame can be eximaned.

Load Kepler.

First a Open file window will be shown. Now the 'Select satellite' window pops up.


Exit the program.

Menu: Edit.

Menu: File header.

Change some items in the file header.


Change orbit/kepler data manually.


All preferences are saved in a file called wsat.ini. This file is read at program-start.
By means of the Preferences window the preference items can easily be changed.
(The wsat.ini file is ASCII, so may also be changed using a text editor.)

The wsat.ini file is searched for in the following directories, in this order:

The first wsat.ini file found is taken.
If no wsat.ini file is found the built-in defaults are taken.

After changing items:

Changes will always be saved in a wsat.ini file in the current directory. Move it to one of the mentioned locations, if desired.

Main window position and size

Decoder interface

Working directory and Kepler files

Record related settings


In other words: If the pixels U, L, R and B have luminance differences of less than 20, and at the same time pixel P has a difference of more than 10 with the surrounding pixels then pixel P is detected as a 'Speckle'. Its value will be changed to the value of pixel D.

Colors and fonts.

Menu: View.

Menu: Zoom

zZoom; click on 2 opposite corners of virtual rectangle
(right-mouse button: cancel)
ZZoom fixed; move rectangle to part of picture in which to zoom anc click
(right-mouse button: cancel)
(See preferences to change fixed-zoom factor.)
{Ctrl}Zoom fixed; see 'Z'
ffull picture (zx=zy=1)
izoom in fixed (default: 2x; see preferences)
ozoom out fixed (default: 2x; see preferences)
llast (previous) zoom
cdx->dy: Make pixel-size dx equal to dy
Cdy->dx: Make pixel-size dy equal to dx

zx->zy: Make zoom-factor zx equal to zy

zy->zx: Make zoom-factor zy equal to zx

Change zoom vars manual.

Menu: Luminance threshold.

Calculate "ideal" picture mapping on grey palette.

Menu: Record.

See preferences to define parallel port and fast par. port access.




Records raw data from parallel port. Not for a specific format.
Bytes from parallel port are dumped in a file, without headers, frame separations etc.

This option is ment for MSG, but can also be used to put raw HRI or HRPT data on disk. With HRPT just the 8 MSB's are recorded (2 LSB's are lost), and channel selection has to be done using the HRPT recording window or with switches on the hardware. (If there is a need to record all 10 bits in raw format let me know.)

The picture on screen during record shows 2048 pixels per line. HRPT and HRI are not shown correctly; MSG recording will (should) show a vertical structure in 8 of the 2048 pixels per line.

Menu: Channel.

Choose a channel to view.

Menu: Help.

Program info and test.

Program info

Test parallel port

This image shows the result of waveforms with HRPT generator, channel 1 selected. This channel is a black-to-white image; data is:

So, the LSB has a high frequency (pin 13), the MSB has the lowest frequency (upper 'data' wave) which is clearly shown in the picture.